过去将来完成进行时
过去将来完成进行时表示从过去某时间开始一直延续到过去未来某一时间的动作，常与由介词by等引导的表示到过去未来的某时的时间副词连用。
形式
由should/would have been + v-ing构成；
否定形式should/would+not have been + v-ing；
疑问形式是将should/would提前。
基本用法
过去将来完成进行时表示动作从过去某一时间开始一直延续到过去将来某一时间。动作是否继续下去，视上下文而定。如：
He said that by the end of the spring term he would have been studying English for three years.
他说到春季（即下）学期末，他将学了三年英语了。
He told me that by the end of the year. he would have been living there for thirty years.
他告诉我，到年底他在那里住了有30年了。